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Organizing programs without classes (1991) [pdf] (au.dk)
41 points by adamnemecek on July 7, 2016 | hide | past | web | favorite | 9 comments

OR: Organizing programs in OOP styles in which class-like manifestations are an emergent phenomenon, while denying the applicability of the word "class" to anything we see.


>All organizational functions carried out by classes can be accomplished in a simple and natural way by object inheritance in classless languages, ...

Like javascript prototypes? Ah, yes.

> ... with no need for special mechanisms.

Is object the type then or a single class?

> A single model—dividing types into prototypes and traits—supports sharing of behavior and extending or replacing representations. A natural extension, dynamic object inheritance, can model behavioral modes. Object inheritance can also be used to provide structured name spaces for well-known objects.

>Classless languages can even express “class-based” encapsulation. These stylized uses of object inheritance become instantly recognizable idioms, and extend the repertory of organizing principles to cover a wider range of programs

It's easy to poke fun at this with 25 years of hindsight. :-)

A version of this in NewtonScript http://waltersmith.us/newton/Class-based%20NewtonScript%20Pr...

Probably still one of my favorite languages and the one that taught me prototype-based inheritance was pretty nice.

closures ?

I am pretty sure there was a Perl book that referred to closures as inside out objects.

That would be a little odd, considering closures are about as objecty as you can get.


The venerable master Qc Na was walking with his student, Anton. Hoping to prompt the master into a discussion, Anton said "Master, I have heard that objects are a very good thing - is this true?" Qc Na looked pityingly at his student and replied, "Foolish pupil - objects are merely a poor man's closures."

Chastised, Anton took his leave from his master and returned to his cell, intent on studying closures. He carefully read the entire "Lambda: The Ultimate..." series of papers and its cousins, and implemented a small Scheme interpreter with a closure-based object system. He learned much, and looked forward to informing his master of his progress.

On his next walk with Qc Na, Anton attempted to impress his master by saying "Master, I have diligently studied the matter, and now understand that objects are truly a poor man's closures." Qc Na responded by hitting Anton with his stick, saying "When will you learn? Closures are a poor man's object." At that moment, Anton became enlightened.


Oh, and of course: COLA (Combined Object Lambda Architecture): http://lambda-the-ultimate.org/node/2483

Actually, no. It was about constructing objects "inside out" (data untouchable from the outside) using closures. This is an accomplishment in a language where object system has data totally open and accessible to anyone.

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